XXIII. BODY CONTROL AND HABIT FORMATION 



Problems. — How is body control jnaintained f 



(a) What is the inechanisiiv of direction and control ? 



(b) What is the method of direction and control? 



(c) What are habits ? How are they formed and how brohen ? 



(d) Wh(t,t are the organs of sense? What are their uses? 

 ie) How does alcohol affect the nervous system? 



Laboratory Suggestions 



Demonstration. — Sensory motor reactions. 



Demonstration. — Nervous system. Models and frog dissections. 



Demonstration. — Neurones under compound microscope (optional). 



Demonstration. — Reflex acts are unconscious acts : show how conscious 

 acts may become habitual. 



Home exercise in habit forming. 



The senses. — Home exercises. — (1) To determine areas most sensitive 

 to touch. (2) To determine or map out hot and cold spots on an area on 

 the wrist. (3) To determine functions of different areas on tongue. 



Demonstration. — Show how eye defects are tested. 



Laboratory summary. — The effects of alcohol on the nervous system. 



The Body a Self-directed Machine. — Throughout the preced- 

 ing chapters the body has been likened to an engine, which, while 

 burning its fuel, food, has done work. If we were to carry our 

 comparison further, however, the simile ceases. For the engineer 

 runs the engine, while the bodily machine is self-directive. 



Moreover, most of the acts we perform during a day's work are 

 results of the automatic working of this bodily machine. The 

 heart pumps ; the blood circulates its load of food, oxygen, and 

 wastes ; the movements of breathing are performed ; the thousand 

 and one complicated acts that go on every day within the body are 

 seemingly undirected. 



Automatic Activity. — In addition to this, numbers of other of 

 our daily acts are not thought about. If we are well-regulated 



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